Valve clearance

I have a 1996 ls 400 that i just had the valves reseated and new valve stem seals. Being new to lexus i mixed uo all the buckets and shims, then put them back in heads. When i cranked the car up a fairly load knocking from top of the engine. Much more than what i would call tick. Could this be because of clearence issues with shims??

I have a 1996 ls 400 that i just had the valves reseated and new valve stem seals. Being new to lexus i mixed uo all the buckets and shims, then put them back in heads. When i cranked the car up a fairly load knocking from top of the engine. Much more than what i would call tick. Could this be because of clearence issues with shims??